|
You can use the DISPLAY EE command to obtain information
about Enterprise Extender. This command has various formats providing
general Enterprise Extender information as well as detailed connection
throughput statistics. A few of the display command formats will be
shown along with some of the important messages. - To display general Enterprise Extender information in summary
format, use the following command:
D NET,EE
- Message IST1685I identifies the job name of the TCP/IP stack which
Enterprise Extender is using.
- Message IST2004I displays the Enterprise Extender Logical Data
Link Control (LDLC) timer and disconnect timer values associated with
the PORT definition statement.
- Message IST2005I shows the number of seconds VTAM® waits for name-to-address resolution requests
to complete before canceling the request. The value displayed is associated
with the Enterprise Extender port and affects only local HOSTNAME
name-to-address resolution requests. When an EE line is in the process
of being activated, and VTAM is
performing name-to-address resolution for the local HOSTNAME, a display
of the line (D NET,ID=linename) will show a state of PGAIN
(Pending GetAddrInfo). If an EE line is hung in PGAIN state, you can
perform the following steps to identify why the local HOSTNAME name-to-address
resolution is not completing:
- Verify that the TCP/IP stack identified in message IST1685I is
active.
- Verify that the TCP/IP resolver is active.
Result: If
IPRESOLV displays the value of 0, VTAM will
wait infinitely for the name-to-address resolution to complete. In
this situation, VTAM relies
on the TCP/IP resolver to time out the resolution. For more information,
see z/OS Communications Server: IP Configuration
Guide.
- IST2008I displays the IP Type of Service (ToS) values associated
with each of the Enterprise Extender port priorities.
- IST2021I displays the total number of active Enterprise Extender
connections.
- To display general Enterprise Extender information in detail,
use the following command:
D NET,EE,DET
- The detailed format of the general Enterprise Extender display
provides detailed information for each local IP address. Message IST1680I
is the first message of a message group. The information for each
local IP address is displayed between the IST924I messages.
For
each local IP address active to Enterprise Extender, the following
information is displayed: - Message IST2004I displays the Enterprise Extender Logical Data
Link Control (LDLC) timer and disconnect timer values used by this
local static VIPA.
- Message IST1910I/IST1911I displays the local HostName (if applicable).
- Message IST2009I displays the total number of RTP pipes traversing
EE connections associated with this local IP address. This message
also displays the total number of LU-LU sessions associated with these
RTP pipes.
- IST2010I displays the number of Enterprise Extender lines which
have been INOPed because of SRQRETRY exhaustion. This count is maintained
from the time the first EE line (associated with this specific local
IP address) is activated, until the last line (associated with this
specific local IP address) is deactivated. When the last line is deactivated
for this local IP address, this counter will be cleared.
- For each VRN, the following information will be displayed:
- Message IST2013I displays the number of available lines for predefined
EE connections associated with this local IP address.
Guideline: Verify
that IST2013I displays enough lines to support the number of predefined
connections that can exist for this local IP address. If the number
of lines is not large enough, new EE connections will fail to connect.
If the number of available lines displays as zero, this might mean
that all Enterprise Extender lines are associated with the Connection
Network (CN) groups. For this case, all available lines that are associated
with CN groups are available for predefined connections as well. Lines
will be selected from the local CN groups first. If no local CN lines
are available, then lines will be selected from the global CN groups.
- To display Enterprise Extender connection information in detail,
use the following command:
D NET,EE,ID=puname or linename,DET
Tip: The
DISPLAY EE commands have various formats in which the connection information
can be displayed. The example here uses the ID=operand. The DISPLAY
EE command with the HOSTNAME/IPADDR operands provides essentially
the same information.
- Message IST2022I displays the date and time of the Enterprise
Extender connection activation.
- Message IST2114I displays the initial, maximum, and current LIVTIME
values for an EE connection.
- Message IST2025I displays the number of LDLC signals over this
EE connection which did not receive a response on the first try. The
signal required at least one retransmission before a response was
received from the EE partner.
- Message IST2026I is closely associated with message IST2025I.
The value displayed here indicates the number of LDLC signals over
this EE connection which did not receive a response up to SRQRETRY
times. It required the signal to be retransmitted SRQRETRY times,
at which time a response was received from the EE partner.
Tip: If
this display is issued repeatedly over a period of time, and the values
displayed in messages IST2025I or IST2026I continue to grow, this
indicates that there is most likely a problem in the network. Network
congestion is a possible problem which might lead to Enterprise Extender
failure. Increasing the LIVTIME, SRQRETRY, and SRQTIME values on the
EE XCA PORT macro will allow Enterprise Extender connections to tolerate
longer network delays. However, if severe network delays are encountered,
it is most likely Enterprise Extender connections will INOP due to
timeout conditions.
- Message IST2029I displays the largest MTU size that Enterprise
Extender will send over the IP network for this connection. When policy-based
routing is in effect, the MTU size might be different for each of
the ports, depending on the routes chosen for EE traffic. This message
is issued for each of the five EE ports regardless of whether policy-based
routing is in effect and regardless of whether the display is for
an IPv4 or IPv6 connection. The MTU size (both IPv4 and IPv6) might
change during the life of the EE connection. The displayed value is
obtained in the following manner: Message IST2029I displays the largest
MTU size that Enterprise Extender will send over the IP network for
this connection. When policy-based routing is in effect, the MTU size
might be different for each of the ports, depending on the routes
chosen for EE traffic. This message is issued for each of the five
EE ports regardless of whether policy-based routing is in effect and
regardless of whether the display is for an IPv4 or IPv6 connection.
The MTU size (both IPv4 and IPv6) might change during the life of
the EE connection. The displayed value is obtained in the following
manner:
- Initially, VTAM queries
the TCP/IP stack for its MTU size and sets the EE connection to use
this value. This MTU size has already been reduced to account for
various header lengths such as the IP, UDP, and LLC headers necessary
for EE traffic.
- VTAM also takes into account
the VTAM MTU operand value,
if specified. The MTU operand may be specified on three types of VTAM major nodes:
- For EE connection networks, this parameter may be defined on the
connection network GROUP definition statements in the EE XCA major
node.
- For dial-in Enterprise Extender connections which have their associated
PUs dynamically created, this parameter may be defined on the model
major node (DYNTYPE=EE) PU definition statement.
- For predefined Enterprise Extender connections, this parameter
may be defined on the PU definition statement in the switched major
node.
- VTAM then takes the lesser
of the TCP/IP stack's computed MTU size and the VTAM defined MTU operand value (if specified).
If the TCP/IP stack presents a value less than 768 bytes, VTAM sets the MTU to 768 because
this is the smallest packet size allowed by the HPR architecture.
- Generally the MTU size for an EE connection is fairly constant
when the EE connection is established. However, in the event the
TCP/IP stack's MTU size changes, RTP pipes with endpoints on the same
node as the TCP/IP stack dynamically detect these changes when their
outbound packets are being transmitted. The MTU size changes because
of the following reasons:
- New IP routes come available with different local MTU sizes
- Existing IP routes become unavailable.
- Path MTU discovery is enabled for IPv4 or IPv6 EE connections
(See the PMTUD start option for details, z/OS Communications Server: SNA Resource Definition
Reference), and path MTU changes are discovered in
the IP network.
- Message IST2038I and IST2039I display the number of packets and
the number of bytes that have been retransmitted. These counts are
displayed for each port priority level. If the values displayed in
these two messages increase over time, this indicates problems within
the transport network. Large numbers of retransmissions due to network
congestions will result in poor RTP performance. If excessive retransmissions
occur, RTP path switching might occur.
|